Why Do Chickens Kill Each Other?

Chickens pecking each other to death isn’t something reserved for the horrendous practice of cock fighting. Even a coop full of sweet little Henny Penny types may kill other chickens in certain conditions. So why do chickens attack each other, sometimes to the death?

Chickens may kill each other for many reasons, including during the establishment of the pecking order, seeing blood, boredom, inadequate nutrition, and overcrowding. Always keep a close eye when introducing new hens to the flock and remove any injured or overly aggressive birds from the coop.

Nobody wants their coop to turn into a reenactment of a classic Hollywood horror flick. Thankfully, rampant cannibalism amongst non-commercial hens is rare. But backyard chickens can become surprisingly aggressive, especially when new hens are introduced or chicks are hatched. A mother might even take out her chick. But chicken owners can reduce the risk of attacks.

Can Chickens Kill Each Other?

Chickens can kill each other. While the dangers of having too many roosters in a flock are pretty well known, even an all-hen coop can become deadly. Researchers have found that some chicken breeds are genetically more aggressive than others. In addition, mixed-breed flocks will have more aggression than flocks of the same breed.

However, owning docile breeds is not the only way to prevent hens from becoming overly aggressive. Many backyard chicken owners and homesteaders have successfully kept mixed-breed flocks without experiencing any significant increase in aggressive behavior. Which isn’t to say accidents don’t happen. But the best prevention is knowing why chickens kill each other.

two cocks look at each other, ready for fight to establish pecking order

Why Do Chickens Attack Each Other?

Chickens almost always attack each other for a specific reason. There is, on occasion, a highly aggressive chicken, and sadly, these sometimes have to be removed to ensure a safe and harmonious flock. But generally, aside from skirmishes, heightened aggression amongst chickens is due to a solvable problem.

Chickens Attack To Establish Pecking Order

Pecking order in chicken flocks is part of their natural hierarchy. The pecking order changes whenever a new chicken is introduced, an old one is reintroduced, or chickens are removed. Generally, the pecking order will be established without them killing each other if they have plenty of room and the chickens are all around the same size. However, extra caution is required at this time.

Introducing New Chickens Is High Risk For Aggression

Introducing new chicken or reintroducing a bird to a flock may cause aggression. The pecking order has to be re-established. To reduce the chaos, do it slowly. If you have young chickens, raise them elsewhere until they are closer to adulthood. You want to avoid significant size differences.

Consider splitting the coop or putting a crate inside when ready to introduce them. Then the new and old chickens can get used to each other without pecking. When merging, consider adding the new ones to the roosting rails at night. Then check on them throughout the day for the next week. Letting the old flock free-range during the day and keeping the new ones in is also a good trick.

If one chicken is causing far too much trouble, remove it temporarily and reintroduce it later. Often that will be enough to curb the aggression to a more reasonable level.

Chickens Are Attracted To Red

Chickens are attracted to red which can cause a wounded bird to become pecked excessively and may lead to death. Fowl can get injured for all sorts of reasons. Should you see one has had an unfortunate incident, remove them from the flock until fully healed. Then slowly reintroduce when ready.

Chickens will harm themselves if they can’t bathe. Dust baths allow chickens to control lice and mites. If they have too many critters in their feathers, they peck at them, sometimes causing injury. If an injury draws the attention of other birds in the flock, they might begin to peck at the wounded chicken, which could escalate into a dangerous situation.

Make sure your flock has room for dust baths. In some cases, diatomaceous earth can help, but it must be mixed in carefully so it doesn’t hang out in the air, as it isn’t good for chickens to breathe it.

Chickens Kill In Overcrowded Coops

Chickens may kill each other in overcrowded coops. Aggression levels are raised in cramped conditions, and eventually, one gets injured, possibly leading to death. If your flock is getting too big, try to find them new homes, build an additional coop, or it may be time to consider reducing the size of the flock.

Bored Chickens Are More Aggressive

Chickens, like children and puppies, can become bored. Their brains are more sophisticated than most people understand and have needs beyond eating and sleeping. They like toys, are curious about new things, and enjoy exploring.

To reduce aggression and potential murderous rage, make sure they have some toys or are let out to explore. If they must be in a coop at all times, consider a chicken tractor, so the enclosure can be moved to a different spot every few days.

Poor Nutrition Can Lead To Chicken Cannibalism

Diet and nutrition’s influence on chicken cannibalism has been investigated since the 1940s. Lack of insoluble dietary fiber, protein, and salts has all been found to cause issues amongst flocks. The problem is more common in large-scale poultry farming than in your average backyard or homestead flocks. In addition, those that are free-range are less likely to have issues.

Nonetheless, if you live in a place where winters are hard or you can’t let your flock free-range, ensure you give them feed that meets their nutritional needs.

Chickens Attack Weakness

Chicken pecking order means weaker chickens, especially hens, are more vulnerable. Chickens can become downright murderous if one of their members is ill or aging toward death. Therefore, monitor any chicken that appears sluggish, unusually droopy, or aging. You may need to remove the weak fowl from the flock for safety if the pecking reaches unsafe levels.

Tip: A sick bird should always be removed from the coop to prevent illness from spreading.

Hens May Accidentally Hurt Their Chicks

Hens are generally excellent mums to their chicks. But they will kill their own if they suspect it is sick or has a deformity for the sake of the rest. Also, some hens are not cut out for motherhood. They might not be mean, simply careless, and accidentally injure or lose their babies. These chicks will be especially vulnerable to attacks from other flock members.

Also, if you have more than one hen raising chicks, it can sometimes be best to separate them into their own areas. The mums are dedicated to their babies, not the others, and will kill if they think their resources are scarce or feel crowded.

Lastly, hens may not recognize chicks they didn’t hatch as their own, and some can act aggressively or even lethally toward them. Thus, you can slip eggs under a broody hen, and when they hatch, she’ll raise them as her own. But introducing orphaned chickens to a hen is more risky. It can happen that the hen will kill them. Therefore it might be a better idea to hand-raise them yourself (look into chicken brooders) and introduce them when they’re bigger.

Chickens May Kill When Hot

Chickens can become irritable in high temperatures, much like humans. They will peck and each other more often, and if the situation is not managed, they might start killing each other. Tips to keep your chickens cool include:

  • Use shade cloth to create cooler areas
  • Ensure the coop is well ventilated
  • Keep the coop clean
  • The flock must have access to fresh, cool water
  • Give them chilled treats, like cut watermelon and other fruit
  • Freeze their feed before giving it to them
  • Set up a shallow pool that they can stand in


Chickens do attack each other, and it can lead to death. Thankfully, it is rare in flocks where they have plenty of space, are not overheated, and are given proper nutrition. Nonetheless, it’s always important to keep an eye on the situation, especially after introducing new birds or if one of your chickens is showing signs of illness or injury.

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